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<p class="banner">SOCI - The C++ Database Access Library</p>

<h2>ODBC Backend Reference</h2>

<div class="navigation">
<a href="#prerequisites">Prerequisites</a><br />
<div class="navigation-indented">
  <a href="#versions">Supported Versions</a><br />
  <a href="#tested">Tested Platforms</a><br />
  <a href="#required">Required Client Libraries</a><br />
</div>
<a href="#connecting">Connecting to the Database</a><br />
     
<a href="#support">SOCI Feature Support</a><br />
<div class="navigation-indented">
    <a href="#dynamic">Dynamic Binding</a><br />
    <a href="#bindingbyname">Binding by Name</a><br />
    <a href="#bulk">Bulk Operations</a><br />
    <a href="#transactions">Transactions</a><br />
    <a href="#blob">BLOB Data Type</a><br />
    <a href="#rowid">RowID Data Type</a><br />
    <a href="#nested">Nested Statements</a><br />
    <a href="#procedures">Stored Procedures</a><br />
</div>
  <a href="#native">Accessing the Native Database API</a><br />
  <a href="#extensions">Backend-specific Extensions</a><br />
<div class="navigation-indented">
    <a href="#odbc_soci_error">ODBCSOCIError</a><br />
</div>
  <a href="#options">Configuration options</a><br />
</div>

<h3 id="prerequisites">Prerequisites</h3>
<h4 id="versions">Supported Versions</h4>

<p>The SOCI ODBC backend is supported for use with ODBC 3.</p>

<h4 id="tested">Tested Platforms</h4>

<table border="1" cellpadding="5" cellspacing="0">
<tbody>
<tr><th>ODBC version</th><th>Operating System</th><th>Compiler</th></tr>
<tr><td>3</td><td>Windows XP</td><td>Visual Studio 2005 (express)</td></tr>
<tr><td>3</td><td>Windows XP</td><td>Visual C++ 8.0 Professional</td></tr>
<tr><td>3</td><td>Windows XP</td><td>(cygwin) g++ 3.3.4</td></tr>
</tbody>
</table>

<h4 id="required">Required Client Libraries</h4>

<p>The SOCI ODBC backend requires the ODBC client library.</p>

<h4 id="connecting">Connecting to the Database</h4>

<p>To establish a connection to the ODBC database, create a Session object
using the <code>ODBC</code> backend factory together with a connection string:</p>

<pre class="example">
BackEndFactory const &amp;backEnd = odbc;
Session sql(backEnd, "filedsn=c:\\my.dsn");
</pre>

<p>or simply:</p>

<pre class="example">
Session sql(odbc, "filedsn=c:\\my.dsn");
</pre>

<p>The set of parameters used in the connection string for ODBC is the same as accepted by the <code><a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odbcsql/od_odbc_d_4x4k.asp">SQLDriverConnect</a></code> function from the ODBC library.</p>

<p>Once you have created a <code>Session</code> object as shown above, you can use it to access the database, for example:</p>
<pre class="example">
int count;
sql &lt;&lt; "select count(*) from invoices", into(count);
</pre>

<p>(See the <a href="../basics.html">SOCI basics</a> and <a href="../exchange.html">exchanging data</a> documentation for general information on using the <code>Session</code> class.)</p>

<h3 id="support">SOCI Feature Support</h3>
<h4 id="dynamic">Dynamic Binding</h4>

<p>The ODBC backend supports the use of the SOCI <code>Row</code> class, which facilitates retrieval of data whose type is not known at compile time.</p>

<p>When calling <code>Row::get&lt;T&gt;()</code>, the type you should pass as T depends upon the underlying database type.<br/>  For the ODBC backend, this type mapping is:</p>

<table border="1" cellpadding="5" cellspacing="0">
  <tbody>
    <tr>
      <th>ODBC Data Type</th>
      <th>SOCI Data Type</th>
      <th><code>Row::get&lt;T&gt;</code> specializations</th>
    </tr>
    <tr>
      <td>SQL_DOUBLE
	    , SQL_DECIMAL
	    , SQL_REAL
	    , SQL_FLOAT
	    , SQL_NUMERIC
	  </td>
      <td><code>eDouble</code></td>
      <td><code>double</code></td>
    </tr>
    <tr>
      <td>SQL_TINYINT
	    , SQL_SMALLINT
	    , SQL_INTEGER
	    , SQL_BIGINT</td>
      <td><code>eInteger</code></td>
      <td><code>int</code></td>
    </tr>
    <tr>
      <td>SQL_CHAR, SQL_VARCHAR</td>
      <td><code>eString</code></td>
      <td><code>std::string</code></td>
    </tr>
    <tr>
      <td>SQL_TYPE_DATE
	    , SQL_TYPE_TIME
	    , SQL_TYPE_TIMESTAMP</td>
      <td><code>eDate</code></td>
      <td><code>std::tm</code><code></code></td>
    </tr>
  </tbody>
</table>

<p>Not all ODBC drivers support all datatypes</p>

<p>(See the <a href="../exchange.html#dynamic">dynamic resultset binding</a> documentation for general information on using the <code>Row</code> class.)</p>

<h4 id="bindingbyname">Binding by Name</h4>

<p>In addition to <a href="../exchange.html#bind_position">binding by position</a>, the ODBC backend supports <a href="../exchange.html#bind_name">binding by name</a>, via an overload of the <code>use()</code> function:</p>

<pre class="example">
int id = 7;
sql &lt;&lt; "select name from person where id = :id", use(id, "id")
</pre>

<p>Apart from the portable "colon-name" syntax above, which is achieved by rewriting the query string, the backend also supports the ODBC ? syntax:</p>

<pre class="example">
int i = 7;
int j = 8;
sql &lt;&lt; "insert into t(x, y) values(?, ?)", use(i), use(j);
</pre>

<h4 id="bulk">Bulk Operations</h4>

<p>The ODBC backend has support for SOCI's <a href="../statements.html#bulk">bulk operations</a> interface.  Not all ODBC drivers support bulk operations, the following is a list of some tested backends:</p>

<table border="1" cellpadding="5" cellspacing="0">
  <tbody>
    <tr>
      <th>ODBC Driver</th>
      <th>Bulk Read</th>
      <th>Bulk Insert</th>
    </tr>
    <tr>
	  <td>MS SQL Server 2005</td>
	  <td>YES</td>
	  <td>YES</td>	
	</tr>
    <tr>
	  <td>MS Access 2003</td>
	  <td>YES</td>
	  <td>NO</td>	
	</tr>
    <tr>
	  <td>PostgresQL 8.1</td>
	  <td>YES</td>
	  <td>YES</td>	
	</tr>
    <tr>
	  <td>MySQL 4.1</td>
	  <td>NO</td>
	  <td>NO</td>	
	</tr>
  </tbody>
</table>

<h4 id="transactions">Transactions</h4>

<p><a href="../statements.html#transactions">Transactions</a> are also fully supported by the ODBC backend, provided that they are supported by the underlying database.</p>

<h4 id="blob">BLOB Data Type</h4>

<p>Not currently supported</p>

<h4 id="rowid">RowID Data Type</h4>

<p>Not currently supported</p>

<h4 id="nested">Nested Statements</h4>

<p>Not currently supported</p>

<h4 id="procedures">Stored Procedures</h4>

<p>Not currently supported</p>

<h3 id="native">Acessing the native database API</h3>

<p>SOCI provides access to underlying datbabase APIs via several getBackEnd() functions, as described in the <a href="../beyond.html">beyond SOCI</a> documentation.</p>

<p>The ODBC backend provides the following concrete classes for navite API access:</p>

<table border="1" cellpadding="5" cellspacing="0">
  <tbody>
    <tr>
      <th>Accessor Function</th>
      <th>Concrete Class</th>
    </tr>
    <tr>
      <td><code>SessionBackEnd* Session::getBackEnd()</code></td>
      <td><code>ODBCSessionBackEnd</code></td>
    </tr>
    <tr>
      <td><code>StatementBackEnd* Statement::getBackEnd()</code></td>
      <td><code>ODBCStatementBackEnd</code></td>
    </tr>
    <tr>
      <td><code>RowIDBackEnd* RowID::getBackEnd()</code></td>
      <td><code>ODBCRowIDBackEnd</code></td>
    </tr>
  </tbody>
</table>


<h3 id="extensions">Backend-specific extensions</h3>
<h4 id="odbc_soci_error">ODBCSOCIError</h4>

<p>The ODBC backend can throw instances of class <code>ODBCSOCIError</code>,
which is publicly derived from <code>SOCIError</code> and has 
additional public members containing the ODBC error code, the Native database error code, and the message returned from ODBC:</p>

<pre class="example">
int main()
{
    try
    {
        // regular code
    }
    catch (SOCI::ODBCSOCIError const &amp; e)
    {
        cerr &lt;&lt; "ODBC Error Code: " &lt;&lt; e.odbcErrorCode() &lt;&lt; endl
             &lt;&lt; "Native Error Code: " &lt;&lt; e.nativeErrorCode() &lt;&lt; endl
             &lt;&lt; "SOCI Message: " &lt;&lt; e.what() &lt;&lt; std::endl
             &lt;&lt; "ODBC Message: " &lt;&lt; e.odbcErrorMessage() &lt;&lt; endl;
    }
   catch (exception const &amp;e)
    {
        cerr &lt;&lt; "Some other error: " &lt;&lt; e.what() &lt;&lt; endl;
    }
}
</pre>
<h3 id="options">Configuration options</h3>

<p>None</p>

<p class="copyright">Copyright &copy; 2004-2006 Maciej Sobczak, Stephen Hutton, David Courtney</p>
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